Gas springs of this type are known from German Pat. No. 18 12 282, for example, which corresponds to U.S. Pat. No. 3,656,593. Because of their advantageous features, these gas springs have proved to be extraordinarily useful in practice, in particular as adjustable-length lifting devices in chair seat support shafts and the like. The valve bodies are fabricated as turned metal parts; that is, the outer grooves for receiving the outer ring seals are produced by recessing feeding, or infeeding. In this turning process, chips can become stuck in the outer groove, and it may not be possible to remove them by subsequent rinsing. Such chips may under some circumstances then remain in the outer groove, causing damage to the outer ring seal during the use of the gas spring, with the result that the gas spring becomes useless.